Digital Commons Network^™

Unmanned Research Vehicle (Urv): Development, Implementation, & Flight Test Of A Mimo Digital Flight Control System Designed Using Quantitative Feedback Theory, Constantine H. Houpis, Steven J. Rasmussen

Faculty Publications

The Quantitative Feedback Theory (QFT) design technique, which has the ability to bridge the gap between theory and the real-world control design problem, is utilized in the design of a MIMO digital flight control system for an unmanned research vehicle (URV) that is presented in this paper. The design illustrates how the real-world knowledge of the plant to be controlled and the desired performance specifications can be utilized in trying to achieve a successful robust design for a nonlinear control problem. This paper presents some of the issues involved in developing, implementing, and flight testing a flight control system (FCS) …

Adaptive Handoff Algorithms Based On Self-Organizing Neural Networks To Enhance The Quality Of Service Of Nonstationary Traffic In Hierarchical Cellular Networks, William S. Hortos

Electrical Engineering and Computer Science Faculty Publications

Third-generation (3G) wireless networks, based on a hierarchical cellular structure (HCS), support tiered levels of multimedia services. These services can be categorized as real-time and delay-sensitive, or non-real-time and delay-insensitive. Each call carries demand for one or more services in parallel; each with a guaranteed quality of service (QoS). Roaming is handled by handoff procedures between base stations (BSs) and the mobile subscribers (MSs) within the network. Metrics such as the probabilities of handoff failure, dropped calls and blocked calls; handoff transition time; and handoff rate are used to evaluate the handoff schemes, which also directly affect QoS. Previous researchers …

Comparative Analysis Of Mobility Management Schemes In A Low Earth Orbit Satellite Network, Stephen R. Conkling

Theses and Dissertations

In the 60's the United States and the Union of Soviet Socialist Republics engaged in a "space race" to be the first to put a man on the moon. Today, the space race is between large multinational telecommunication corporations with the winner receiving the financial rewards by providing communication services to the billions without even a simple telephone. Many entrants are using Low Earth Orbit (LEO) satellites to provide the communications infrastructure, but the number of customers a satellite can support is limited by bandwidth available. This resource must be used efficiently, and this involves reducing the management overhead. This …

Development Of A Real Time Guidance System For A Kinematic Test Vehicle, Orhan Cekic

Theses and Dissertations

Differential carrier phase GPS measurements are capable of giving centimeter-level accuracies. These accuracies have many potential applications for safety and control of various types of vehicles. For this research, a real-time guidance system is developed. The real-time guidance system can be divided into two components: hardware and software. The hardware component consists of two GPS receivers (one base, one mobile), two wireless 115 Kbaud transceivers, and two laptop computers. One computer is for the reference station and other is for the mobile receiver interface and graphical display. The guided vehicle is a golf car called the Remote Sensing Autonomous Vehicle …

Realtime Color Stereovision Processing, Byron P. Formwalt

Theses and Dissertations

Recent developments in aviation have made micro air vehicles (MAVs) a reality. These featherweight palm-sized radio-controlled flying saucers embody the future of air-to-ground combat. No one has ever successfully implemented an autonomous control system for MAVs. Because MAVs are physically small with limited energy supplies, video signals offer superiority over radar for navigational applications. This research takes a step forward in real time machine vision processing. It investigates techniques for implementing a real time stereovision processing system using two miniature color cameras. The effects of poor-quality optics are overcome by a robust algorithm, which operates in real time and achieves …

Post-Processing Resolution Enhancement Of Open Skies Photographic Imagery, Daniel E. Sperl

Theses and Dissertations

The Treaty on Opens Skies allows any signatory nation to fly a specifically equipped reconnaissance aircraft anywhere over the territory of any other signatory nation. For photographic images, this treaty allows for a maximum ground resolution of 30 cm. The National Air Intelligence Center (NAIC), which manages implementation of the Open Skies Treaty for the US Air Force, wants to determine if post-processing of the photographic images can improve spatial resolution beyond 30 cm, and if so, determine the improvement achievable. Results presented in this thesis show that standard linear filters (edge and sharpening) do not improve resolution significantly and …

Tool-Based Integration And Code Generation Of Object Models, Michael Ray Ashby

Theses and Dissertations

Today many organizations are faced with multiple large legacy data stores in different formats and the need to use data from each data store with tools based on the other data stores' formats. This thesis presents a tool-based methodology for integrating object-oriented data models with automatic generation of code. The generated code defines a global data format, generates views of global data in individual integrated data formats, and parses data from individual formats to the global formats and from the global format to the individual formats. This allows for legacy data to be translated into the global format, and all …

Evaluation Of A Method For Kinematic Gps Carrier-Phase Ambiguity Resolution Using A Network Of Reference Receivers, Brian L. Bracy

Theses and Dissertations

New applications for GPS have driven a demand for increased positioning accuracy. The emerging GPS technology particularly affects the test community. The testing equipment and method must provide a solution that is an order of magnitude more precise than the tested equipment to achieve the desired accuracy. Carrier-phase differential GPS methods using a network of reference receivers can provide the centimeter-level accuracy required over a large geographical area. This thesis evaluates the performance of a 5-receiver network over a 50 km x 120 km area of New Mexico, using a GPS network algorithm called NetAdjust. The percentage of time a …

Investigation Of Ge2Te2Sb5 Chalcogenide Thin Film For Use As An Analog Memory, Travis F. Blake

Theses and Dissertations

This work investigates the feasibility of using Ge₂Te₂Sb₅ chalcogenide films for analog memory. Thick film chalcogenide memory devices provided by Ovonyx, Inc. are characterized to determine how well the devices meet the repeatability, stability and predictability criteria needed to accurately store analog data values. Chalcogenide memory devices take advantage of the phase-shifting nature of chalcogenide materials to store the analog data as a resistance level. An automated test system was developed to characterize the material and the prototype devices with the goal to determine the 1) non-destructive readability of the device at different resistance values; …

Design And Validation Of An Accurate Gps Signal And Receiver Truth Model For Comparing Advanced Receiver Processing Techniques, Phillip Martin Corbell

Theses and Dissertations

Recent increases in the computational power of computers and digital signal processors have made possible new, novel signal tracking techniques in GPS receivers. One such technique is known as Direct Correlators Output Processing (DCOP). This technique replaces individual traditional tracking loops with a single Kalman Filter, which jointly processes the received signals while exploiting their correlated noises. DCOP is innovative in its potential to replace the tried and true classical signal tracking loops. It is also an enabling technology for ultra-tightly coupled GPS/INS (Global Positioning System/Inertial Navigation System). Potential benefits of these new tracking techniques include an order-of-magnitude improvement in …

Behavioral Igbt Modeling For Predicting High Frequency Effects In Motor Drives, Jerry L. Tichenor, S. D. Sudhoff, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A first-order behavioral IGBT/gate drive model is proposed together with a procedure for deriving all model parameters. Despite the simplicity of the proposed model, comparison of model predictions with hardware measurements demonstrate the model to be accurate in predicting turn-on and turn-off transients.

Multilevel Coded Modulation For Unequal Error Protection And Multistage Decoding—Part I: Symmetric Constellations, Robert H. Morelos-Zaragoza, Marc P. C. Fossorier, Shu Lin, Hideki Imai

Faculty Publications

In this paper, theoretical upper bounds and computer simulation results on the error performance of multilevel block coded modulations for unequal error protection (UEP) and multistage decoding are presented. It is shown that nonstandard signal set partitionings and multistage decoding provide excellent UEP capabilities beyond those achievable with conventional coded modulation. The coding scheme is designed in such a way that the most important information bits have a lower error rate than other information bits. The large effective error coefficients, normally associated with standard mapping by set partitioning, are reduced by considering nonstandard partitionings of the underlying signal set. The …

Collaborative Distance Education In Power Engineering, Anil Pahwa, Shelli K. Starrett, Kraig J. Olejniczak, S. D. Sudhoff, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a perspective on offering "shared-courses," or courses simultaneously offered at two or more universities via various distance educational frameworks. Over a three year duration, two senior/graduate level courses were jointly developed and offered to the students at the University of Missouri--Rolla, the University of Arkansas, Kansas State University, and Purdue University. This paper discusses the various distance educational technologies including two-way audio/visual via ISDN line, video-tapes, and web-based conferencing. Both instructor and student reactions to these mediums are included. Pedagogical methods appropriate for these mediums are outlined. The paper concludes with recommendations and strategies for engineering institutions …

On The Assessment Of Stability And Patterning Of Speech Movements, Anne Smith, Michael T. Johnson, Clare Mcgillem, Lisa Goffman

Electrical and Computer Engineering Faculty Research and Publications

Speech requires the control of complex movements of orofacial structures to produce dynamic variations in the vocal tract transfer function. The nature of the underlying motor control processes has traditionally been investigated by employing measures of articulatory movements, including movement amplitude, velocity, and duration, at selected points in time. An alternative approach, first used in the study of limb motion, is to examine the entire movement trajectory over time. A new approach to speech movement trajectory analysis was introduced in earlier work from this laboratory. In this method, trajectories from multiple movement sequences are time- and amplitude-normalized, and the STI …

Space/Time/Frequency Methods In Adaptive Radar, Christopher D. Peckham

Dissertations

Radar systems may be processed with various space, time and frequency techniques. Advanced radar systems are required to detect targets in the presence of jamming and clutter. This work studies the application of two types of radar systems.

It is well known that targets moving along-track within a Synthetic Aperture Radar field of view are imaged as defocused objects. The SAR stripmap mode is tuned to stationary ground targets and the mismatch between the SAR processing parameters and the target motion parameters causes the energy to spill over to adjacent image pixels, thus hindering target feature extraction and reducing the …

Integrated Product And Process Development Methodologies For Environmentally Conscious Electronic Products, Pingtao Yan

Dissertations

This research focuses on integrated product and process development (IPPD) methodologies for environmentally conscious electronic products. After a review of current research issues in the field of product and process development, a generic framework for IPPD is proposed which describes most of the concerned issues formally as constrained optimization problems. These problems may include such optimization objectives as cost, benefit, and environmental impact. Based on this framework, an IPPD methodology is proposed as a systems approach to competitive and environmentally conscious product and process development. A case study on personal computer development is performed illustrating how to apply the methodology …

Data Hiding In Multimedia - Theory And Applications, Mahalingam Ramkumar

Dissertations

Multimedia data hiding or steganography is a means of communication using subliminal channels. The resource for the subliminal communication scheme is the distortion of the original content that can be tolerated. This thesis addresses two main issues of steganographic communication schemes:

1. How does one maximize the distortion introduced without affecting fidelity of the content?

2. How does one efficiently utilize the resource (the distortion introduced) for communicating as many bits of information as possible? In other words, what is a good signaling strategy for the subliminal communication scheme?

Close to optimal solutions for both issues are analyzed. Many techniques …

Editing Mpeg2 Video In Compressed Domain, Ren Egawa

Theses

As MPEG2 becomes the heart of most digital video applications, the need to edit an MPEG2 bitstream video in compressed domain has increased. To realize this need, two major technical issues must be resolved: decoder buffer and segment extraction.

In the decoder buffer issue, the edited stream must ensure that the buffer would not overflow or underfiow as the result of the editing. This thesis invented a mathematical model that could describe the editing task and predict the editing effect on the buffer. Based on this model, the thesis then built a method to edit a stream safely. This method …

Electroluminescent Display Device Including Active Polymer Layer, Aemilianus G. J. Staring, David Braun, Karel E. Kuijk

Electrical Engineering

Control device for an electroluminescent display device, comprising an active layer of a semiconducting polymer of, for example pixels arranged in the form of a matrix, reducing flicker and crosstalk. The control device may be based on voltage control at which voltages across the pixels are at least 1.6 V, but is preferably based on current control, at which the duration of the data pulses determines the grey level.

Dislocation Density In Gan Determined By Photoelectrochemical And Hot-Wet Etching, P. Visconti, K. M. Jones, Michael A. Reshchikov, R. Cingolani, Hadis Morkoç, R. J. Molnar

Electrical and Computer Engineering Publications

Defects in GaN layers grown by hydride vapor-phase epitaxy have been investigated by photoelectrochemical (PEC)etching, and by wet etching in hot H3PO4acid and molten potassium hydroxide (KOH). Threading vertical wires (i.e., whiskers) and hexagonal-shaped etch pits are formed on the etched sample surfaces by PEC and wet etching, respectively. Using atomic-force microscopy, we find the density of “whisker-like” features to be 2×109 cm−2, the same value found for the etch-pit density on samples etched with both H3PO4 and molten KOH. This value is comparable to the dislocation density obtained in similar samples with tunnelingelectron microscopy, and is also consistent with …

Well-Width Dependence Of The Ground Level Emission Of Gan/Algan Quantum Wells, A. Bonfiglio, M. Lomascolo, G. Traetta, R. Cingolani, A. Di Carlo, F. Della Sala, P. Lugli, A. Botchkarev, H. Morkoç

Electrical and Computer Engineering Publications

We have performed a systematic investigation of GaN/AlGaN quantum wells grown on different buffer layers (either GaN or AlGaN) in order to clarify the role of strain, structural parameters, and built-in field in determining the well-width dependence of the ground level emission energy. We find that identical quantum wells grown on different buffer layers exhibit strong variation of the ground level energy but similar well-width dependence. The data are quantitatively explained by an analytic model based on the envelope function formalism which accounts for screening and built-in field, and by a full self-consistent tight binding model.

Characterization Of Poly-Si Thin Films Deposited By Magnetron Sputtering Onto Ni Prelayers, Elena A. Guliants, Wayne A. Anderson

Electrical and Computer Engineering Faculty Publications

A method of producing a polycrystalline silicon thin film on a foreign substrate without subsequent annealing has been developed. Thermally evaporated 5–100 nm thick Nifilms served as prelayers for magnetron sputtered Si thin films. A continuous film was obtained as a result of metal induced growth of polysilicon during low temperature (below 600 °C) deposition. The film uniformity is promising for large area device applications. The influence of the Ni prelayer thickness on the grain size of thus obtained films was investigated. Atomic force microscopy and cross-sectional scanning electron microscopy studies revealed features in the 150–600 nm size range while …

On The Error Performance Of 8-Vsb Tcm Decoder For Atsc Terrestrial Broadcasting Of Digital Television, Dojun Rhee, Robert H. Morelos-Zaragoza

Faculty Publications

The error performance of various 8-VSB TCM decoders for reception of terrestrial digital television is analyzed. In previous work, 8-state TCM decoders were proposed and implemented for terrestrial broadcasting of digital television. In this paper, the performance of a 16-state TCM decoder is analyzed and simulated. It is shown that not only a 16-state TCM decoder outperforms one with 8-states, but it also has much smaller error coefficients.

Small Planar Monopole Covers Multiband Brans, Max Ammann, L. E. Doyle

Conference papers

The use of a single antenna which can cover a wide range of frequencies is a desirable feature for future wireless communications systems. The emerging self-organising and ad-hoc networks require more than an octave of bandwidth to facilitate multiband operation. A shorted planar monopole antenna is optimised for future wireless networking bands by suitable choice of planar dimension and feedgap separation. The antenna offers a return-loss greater than 10 dB from 1.60 GHz to 5.90 GHz. The radiation pattern is shown to be quasi-omnidirectional within the 10 dB return-loss bandwidth. Antenna properties are compared with the simple planar monopole.

A Review Of Battery Exchange Technology For Refueling Of Electric Vehicles, C. Arthur Maccarley

Electrical Engineering

The limited energy storage and long recharge time and of electric vehicle batteries have motivated several alternatives to in-vehicle slow charging. Solutions generally fall into three categories: (1) fast charging, in which batteries are charged in-vehicle at an accelerated rate, (2) battery material reloading or refueling, in which the energy-carrying elements of the battery are physically replaced or replenished, and (3) battery interchange, involving the complete exchange of the battery pack, usually with the aid of some semi-automated mechanism. Among these options, the last, battery interchange, has tended to receive the least industry attention, but has been an expansive topic …

Implementations Of Bidirectional Reordering Algorithms, Steven Atkin, Ryan Stansifer

Electrical Engineering and Computer Science Faculty Publications

The goal of this paper is to contribute to a deeper understanding of the Unicode Bidirectional Reference Algorithm. We have provided an alternative reference algorithm written in the functional language Haskell. The advantage of Haskell is it allows for a short, clear description of a complex problem. We have run our algorithm, the two Unicode reference implementations, and four others (ICU, PGBA, FriBidi, JDK 1.2) to test for compliance with the published standard. Conclusions are difficult to reach, but problems were found in the implementations and descriptions and above all with a character-stream to character-stream interpretation of the display of …

Convergence Of Parameter And Delay Estimates Using Open Loop Time Domain Gradient Methods, Aidan O'Dwyer, John Ringwood

Conference papers

This paper discusses the estimation of the parameters of a single input, single output (SISO) process, modelled in first order lag plus delay (FOLPD) form, using gradient methods in the open loop time domain. The paper considers the convergence of the process parameters to the model parameters. The convergence of the model delay is discussed first, when the non-delay model and process parameters are identical. The convergence of all of the model parameters is then considered, when all of the process parameters are unknown.

A Pseudo Spot Price Algorithm Applied To The Pumped-Storage Hydraulic Unit Scheduling Problem, Sali̇h Fadil, Celal Yaşar

Turkish Journal of Electrical Engineering and Computer Sciences

A lossy electric power system that contains thermal units and a pumped-storage hydraulic unit is considered in this paper. The total cost of thermal units in an operation cycle is minimized under some possible electric and hydraulic constraints of the units. The operation cycle is divided into time intervals where the system loads are assumed to remain constant. The proposed solution technique has two main parts. In the first part, the active thermal generations and active generation or pumping power of the pumped-storage unit in all time intervals are determined by using units' active generation incremental costs and pseudo spot …

A Schooling On Their Implications For Software Engineering [Trends], Ann K. Miller

Electrical and Computer Engineering Faculty Research & Creative Works

A discussion is presented on trends in software engineering. This can be done by simply extrapolating some of the popular, current trends. And, in fact, we examine a few of these obvious indicators. However, software engineering has had new approaches that are more revolutionary than evolutionary. In particular, we try to discern trends in software engineering based on trends in delivered software systems.

Distance Spectra For Trellis Coded Modulation Schemes On Channels With Intersymbol Interference, Sabi̇re Haciömeroğlu, Melek D. Yücel

Turkish Journal of Electrical Engineering and Computer Sciences

The effect of intersymbol interference on distance spectra for trellis coded 8-PSK, 16-QAM and 32-AMPM modulation schemes is evaluated using the methods proposed by Schlegel. Distance spectra of 16-state 8-PSK scheme are computed for different intersymbol interference channels. It is seen that on channels with intersymbol interference the spectral lines are spread into a nearly continuous spectrum and the minimum Euclidean distance between codewords decreases severely. Hence, although the main contribution at large signal to noise ratios comes from the minimum Euclidean distance ( d_{free} ) , higher spectral components also become very important at moderate values of the signal …